/**
 * Created by Administrator on 2019/5/23.
 */
function up(n) {
    var a1 =Number(document.querySelector("#z1").value);
    var a2 = Number(document.querySelector("#z2").value);
    if(n==1){
        var c3 =a1+a2
        document.querySelector("#z3").value=c3
    }
    if(n==2){
        var c4 =a1-a2
        document.querySelector("#z3").value=c4
    }
    if(n==3){
        var c5 =a1*a2
        document.querySelector("#z3").value=c5
    }
    if(n==4){
        var c6 =a1/a2
        document.querySelector("#z3").value=c6
    }
}